<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2009, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * SHA1 Encoding Class
 *
 * Purpose: Provides 160 bit hashing using The Secure Hash Algorithm
 * developed at the National Institute of Standards and Technology. The 40
 * character SHA1 message hash is computationally infeasible to crack.
 *
 * This class is a fallback for servers that are not running PHP greater than
 * 4.3, or do not have the MHASH library.
 *
 * This class is based on two scripts:
 *
 * Marcus Campbell's PHP implementation (GNU license)
 * http://www.tecknik.net/sha-1/
 *
 * ...which is based on Paul Johnston's JavaScript version
 * (BSD license). http://pajhome.org.uk/
 *
 * I encapsulated the functions and wrote one additional method to fix
 * a hex conversion bug. - Rick Ellis
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Encryption
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/general/encryption.html
 */
class CI_SHA {

  function CI_SHA() {
    log_message('debug', "SHA1 Class Initialized");
  }

  /**
   * Generate the Hash
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function generate($str) {
    $n = ((strlen($str) + 8) >> 6) + 1;

    for ($i = 0; $i < $n * 16; $i++) {
      $x[$i] = 0;
    }

    for ($i = 0; $i < strlen($str); $i++) {
      $x[$i >> 2] |= ord(substr($str, $i, 1)) << (24 - ($i % 4) * 8);
    }

    $x[$i >> 2] |= 0x80 << (24 - ($i % 4) * 8);

    $x[$n * 16 - 1] = strlen($str) * 8;

    $a =  1732584193;
    $b = -271733879;
    $c = -1732584194;
    $d =  271733878;
    $e = -1009589776;

    for ($i = 0; $i < count($x); $i += 16) {
      $olda = $a;
      $oldb = $b;
      $oldc = $c;
      $oldd = $d;
      $olde = $e;

      for($j = 0; $j < 80; $j++) {
        if ($j < 16) {
          $w[$j] = $x[$i + $j];
        }
        else {
          $w[$j] = $this->_rol($w[$j - 3] ^ $w[$j - 8] ^ $w[$j - 14] ^ $w[$j - 16], 1);
        }

        $t = $this->_safe_add($this->_safe_add($this->_rol($a, 5), $this->_ft($j, $b, $c, $d)), $this->_safe_add($this->_safe_add($e, $w[$j]), $this->_kt($j)));

        $e = $d;
        $d = $c;
        $c = $this->_rol($b, 30);
        $b = $a;
        $a = $t;
      }

      $a = $this->_safe_add($a, $olda);
      $b = $this->_safe_add($b, $oldb);
      $c = $this->_safe_add($c, $oldc);
      $d = $this->_safe_add($d, $oldd);
      $e = $this->_safe_add($e, $olde);
    }

    return $this->_hex($a).$this->_hex($b).$this->_hex($c).$this->_hex($d).$this->_hex($e);
  }

  // --------------------------------------------------------------------

  /**
   * Convert a decimal to hex
   *
   * @access	private
   * @param	string
   * @return	string
   */
  function _hex($str) {
    $str = dechex($str);

    if (strlen($str) == 7) {
      $str = '0'.$str;
    }

    return $str;
  }

  // --------------------------------------------------------------------

  /**
   *  Return result based on iteration
   *
   * @access	private
   * @return	string
   */
  function _ft($t, $b, $c, $d) {
    if ($t < 20)
      return ($b & $c) | ((~$b) & $d);
    if ($t < 40)
      return $b ^ $c ^ $d;
    if ($t < 60)
      return ($b & $c) | ($b & $d) | ($c & $d);

    return $b ^ $c ^ $d;
  }

  // --------------------------------------------------------------------

  /**
   * Determine the additive constant
   *
   * @access	private
   * @return	string
   */
  function _kt($t) {
    if ($t < 20) {
      return 1518500249;
    }
    else if ($t < 40) {
        return 1859775393;
      }
      else if ($t < 60) {
          return -1894007588;
        }
        else {
          return -899497514;
        }
  }

  // --------------------------------------------------------------------

  /**
   * Add integers, wrapping at 2^32
   *
   * @access	private
   * @return	string
   */
  function _safe_add($x, $y) {
    $lsw = ($x & 0xFFFF) + ($y & 0xFFFF);
    $msw = ($x >> 16) + ($y >> 16) + ($lsw >> 16);

    return ($msw << 16) | ($lsw & 0xFFFF);
  }

  // --------------------------------------------------------------------

  /**
   * Bitwise rotate a 32-bit number
   *
   * @access	private
   * @return	integer
   */
  function _rol($num, $cnt) {
    return ($num << $cnt) | $this->_zero_fill($num, 32 - $cnt);
  }

  // --------------------------------------------------------------------

  /**
   * Pad string with zero
   *
   * @access	private
   * @return	string
   */
  function _zero_fill($a, $b) {
    $bin = decbin($a);

    if (strlen($bin) < $b) {
      $bin = 0;
    }
    else {
      $bin = substr($bin, 0, strlen($bin) - $b);
    }

    for ($i=0; $i < $b; $i++) {
      $bin = "0".$bin;
    }

    return bindec($bin);
  }
}
// END CI_SHA

/* End of file Sha1.php */
/* Location: ./system/libraries/Sha1.php */